Rock polishing machine



May 18, 1965 R. K. wRiGHr 3,183,630

I ROCK POLISHING MACHINE Filed Nov. 4, 1963 ROYAL K. WRIGHT BY @MMM CSZWWM ATTORNEYS United States Patent O 3,183,630 RQCK POLISHIN G MACHINE Royal K. Wright, 9900 W. 44th Ave., Wheatridge, Colo. Filed Nov. 4, 1963, Ser. No. 321,090 6 Claims. (Cl. 51-163) This invention relates t lapidary equipment and, more particularly, to a rock polishing machine having a novel vibratory suspension incorporating a variable amplitude adjustment mechanism.

Lapidary has become increasingly popular in recent years as both a hobby and a commercial enterprise, It is no longer coniined to polishing precious stones for display in jewelry and the like, but rather, has been extended to embrace polishing and cutting of very ordinary rocks of the type readily found along any stream bed or hillside that have no particular worth in their virgin state. When polished, however, these rocks are quite beautiful and are used in various specimen displays, as material to be inlaid into decorative `furniture such as, for example, coffee tables, and as non-precious gem stones for use in inexpensive costume jewelry.

In order to polish these non-precious stones economically, the polishing operation must be conducted on a fairly large scale rather than one-at-a-time as is possible with precious stones. The answer to this, of course, is a polishing machine that will handle many stones at one time.

The prior art rock polishing machines possessed certain disadvantages that rendered them somewhat unsatisfactory for general use. For example, most of these machines provide for only fone amplitude yand frequency of vibratory motion; yet, the materials to be polished vary widely in their hardness and abrasiveness which necessitates special handling to insure their being polished within a reasonable time without producing an excessive amount of dust, nes and even breakage. In other words, soft materials must be vibrated very gently or they will substantially disintegrate during the polishing foperation. Hard substances, on the other hand, are barely effected by gentle vibration thus necessitating more violent tumbling and interaction to produce the desired end result.

Many machines -are so constructed that they cannot withstand the action of the rocks tumbling over one another and against .the sides and bottom without wearing through very rapidly requiring frequent replacement of the container in which the rocks are placed. Previous attempts to solve this problem have met with little success and it still remains a major shortcoming of the existing equipment.

Other units mount the motor in` such a manner that it is subjected to much the same vibratory action as the rock chamber. This, of course, m-aterially shortens bearing life, increases brush wear and otherwise overloads the motor to a point where it fails prematurely. Also, the weight of the motor in such an installation necessitates extra heavy vibratory mountings and can seriously impair the action of the machine.

The vibratory mountings of the prior art machines also leave much to be desired. Some are so constructed that much of the motion imparted thereto by the motor is damped out before it reaches the material being polished thus making the machines most ineiiicient. This is, in large measure, a result of attempting to apply the techniques of shock-absorbent mounts to vibratory machines when, in fact, the desired end results are exactly opposite one another.

Still other units are complex, bulky and expensive. Some are greatly over-powered for the work done due to ineiiciencies in transferring power to the vibrating vessel.

3,l83,630 Patented May 18, 1965 .ICC

In the instant rock polishing machine, on the 'other hand, these diculties are, in large measure, eliminated. For instance, a lightweight rugged open frame is employed as a support for both the motor and vibrating vessel. 'I'he motor is mounted on a fixed base and operatively connected to the vibrating vessel by belts which function to damp out the vibr-atory motion before it gets back to the motor where it can cause damage. This damping action of the belts, however, does not lessen the eflicient transfer of the motors power to the vibratory vessel as the motors sole function is to turn a shaft that carries eccentric weights. This shaft is connected directly to the vibrating vessel so that none of the vibratory effect of the eccentric weights is lost in transmission.

The amplitude of vibration can be varied lover rather wide limits and controlled very accurately through the use of two relatively rotatable eccentric weights. The phasing of these weights determines the gentleness or severity of the vibratory action.

The vibrating vessel itself is'spring-suspended so that the effect of the eccentrics is fully realized. This spring suspension serves the secondary function of a belt tightener to keep the belt under constant tension.

The rock-holding vessel has a rounded bottom that tends to tumble the contents back into the center, otherwise, some material migrates into the corners and is lett substantially untouched. The vessel is lined with a removable resilient liner that promotes mixing and agitation as the material bounces otf the sides. At the same time, it is subjected to very little wear as the abrasive materials tend to bounce around on it rather than slide which is the major factor in premature failure. When the liner does wear through, it can be slipped out of the vessel and replaced without having to discard the whole vessel as is the case with bonded liners.

It is, therefore, the principal object of the present invention to provide a novel and improved rock polishing machine.

A second object of the invention herein described is the provision of a unit of the type aforementioned that employs an improved vibratory assembly which is more efficient, simpler, and longer-lasting than thoseheretofore used.

Another object is the provision of amplitude control for the vibratory action to adapt the unit to various different materials.

Still another objective of the invention herein claimed is to provide a novel power transmission mechanism and arrangement that substantially isolates the motor from the vibratory forces, yet, utilizes the latter to the fullest where they are needed, namely, in the rock container;

An additional object is to provide a rock polisher that incorporates a resilient liner which enhances the polishing operation while, at the same time, prolongs the useful life of the vibrating Vessel.

Further objects are to provide Aa polishing machine that is compact, rugged, versatile, simple'to construct and use, inexpensive, maintenance-free, eicient and decorative in appearance. f

Other objects willl be in part apparent and in part pointed out specifically hereinafter in connection with Vthe description of the drawings that follows, and in which: FIGURE l is a side elevation of the rock polishing machine, portions of which have been broken away and shown in section to better reveal the interior construction;

FIGURE 2 is a section taken along line 2 2 of FIG- URE 1;

FIGURE 3 is a transverse section taken along line 3 3 of FIGURE 2;

FIGURE 4 is an enlargedfragmentary detail of the relatively rotatable eccentrics; and

arsaeao FIGURE is an end View of said eccentrics with a portion of one broken away to reveal the set-screw fastener.

Referring now to the drawings for a detailed description of the invention and, initially, to FIGURES l, 2, and` 3 for this purpose, the rock polishing machine will be seen to include a floor-mounted frame that supports an electric motor 12 and has a platform 14 suspended therefrom by springs 16 which carriesthe rock-holding vessel 18. The frame 10 is fabricated from tubular stock and includes a base 20 to which the motor 12 is fastened. Rubber-tipped legs 22 extend upward from the corners of the base, the latter being substantially square in the particular form illustrated. Front and rear braces 24 connect the upper extremities of the legs leaving both sides open except for a pair of cross braces 26 located about midway upon the frame extending from front to rear.

Platform 14 is rectangular and approximately the same depth as the frame but somewhat narrower so that it will t between the legs and have ample clearance to vibrate as is shown most clearly in FIGURE 3. Hooks `28 are located at the four corners of the platform projecting upwardly therefrom and similar hooks 36 are fastened to the underside of braces 24 in vertically-spaced relation to the hooks 28.

Springs 16, as shown, are of the close-wound tension type and are attached between the four pairs of hooks 2S and 30. Thus, the platform is resiliently suspended from the frame slightly over half way up. As will be explained presently, the vibratory motion imparted to the vessel 18 by the motor is primarily back and forth rather than from side-to-side so that the platform clears the frame at all times. In other words, the action is to the left and right as viewed in FIGURE 3 so that vthe plaform swings through the open sides of the frame.

The `rock-holding vessel 18 is fabricated of cast metal and formed to provide a semi-cylindrical bottom `52, the axis of which extends'gen'erally normal to the direction of vibratory motion. In other words the axis of the semicylindrical bottom goes from side-to-side while the vessel vibrates from front to rear as aforesaid. This is important because it promotes the tumbling and abrasive inter action between the materials being polished because they are thrown up the concave surfaces whereupon they roll back down and are kept in more or less constant motion. Also, the shape of the vessel bottom and its orientation Y position although to a lesser extent.

realtive to the direction of vibratory movement keeps the t material thoroughly mixed so that all portions thereof are subjected to approximately the same degree of polishing action.

The front and rear walls 34 of the vessel are essentially` t planar and they have been shown sloping up and slightly away from one another. The end walls 36, on the other hand, have been shown to lie planar and essentially parallel.

The inside of the vessel 1S is covered in its entiretyv by a removable resilient liner 318V that conforms with the interior wall surfaces and'has aN peripheral lip 40 l (PIG- URE 2) overlying the top edge. fabricated from tough abrasion-resistant rubber and is instantly removable from inside the vessel. The slight f divergence of the walls 34 assists in the removal of the liner.

as it is agitated. Furthermoratheliner has a higher coefficient of friction than the vessel `walls thus aiding in the rolling Yaction of the individual stones rather than letting them slip back downV into Athe bottom.

` The top of the vessel is covered by a lid42 that has a This liner is preferably` The function of the liner, `as aforementioned, `is f to protect the walls ofthe vessel and also to promote the Y mixing of the material by bouncing the particles `around flange 44 on the underside'thereof that fits inside `the',`

liner 38. The right and Vleft ends of the lid have an ear 46 projecting therefrom thatoverlies a corresponding earV 48` on the end'of the vessel. YThese ears are detachably connected together by a Wingnut fasteners@ that holds the as is the interior of the vessel. This is because the contents seldom, if ever, Contact the lid to an extent which would cause wear.

Vessel 18 is fastened to-the platform 14 by means of ears 52 projecting from the integrally-formed Web-like extensions 54 of the sidewalls 36. These ears 52 overlie corresponding ears 56 on the edges of theV platform and the resulting superimposed pairs are, once again, connected by fasteners 58.

The vibratory motion is imparted to the rockholding vessel 13 by an eccentric assembly located underneath the platform and operatively connected to the motor, said assembly having been designated broadly by reference numeral 60. Bolted to the underside of the platform are a pair of bearings 62 arranged in transversely-spaced relation such that shaft 64 mounted therein will parallel the motor shaft 66. Both ends of both the motor shaft and eccentric shaft carry V-belt pulleys 68 and 70, respectively, that are operatively interconnected by V-belts 72.

Now, the spacing between the shafts is such that the V-belts place the springs 16 under slight tension and these springs, therefore, function as belt tighteners along with their primary function of resiliently'supporting the platform and rock-holding vessel.' The springs and belts also cooperate to limit the motion of the vessel induced by the eccentrics 74 and 76 that will be explained presently. The eccentrics, of course, have their center of mass displaced frorn the axis of shaft64 and, therefore, would ordinarily cause the shaft and associated.v structures to describe a circular path in a plane normal to the shaft axis. The V-belts 72,`however, do'not stretch appreciably to allow the platform and vessel to raise up above its static position. Conversely, the pre-tensioned springs 16 function to oppose movement of the platform below its static The net result of the above is to restrict the motion induced by the eccentrics to primarily a back and forth shaking action which has proved most satisfactory for polishing operations because the rocks are not tumbled so violently thatrthey break apart; yet the action is sufficient to `produce the necessary abrasive `interaction needed to polish them. In actuality, the motion approximates that of a narrow elliptical path with the major axis horizontal. Thus, the springs and V-belts cooperate to materially alter and improve the motion ordinarily induced by eccentrics 74 and 76.

As has already been mentioned, the above-described arrangement also materially reduces the damaging eccentric loading on the motor shaft 66 and its bearings. In practice, very little vibratory motion is transmitted to the motor through either the V-belts or the frame because of the novel arrangement just described. `On the other hand, the needed motion is quite'eicently transmitted to the rock vessel which, of course, is the primary objective of the device.

Finally, with reference to FIGURES 4 and 5, it will be seen how the variations in the amplitude of the vibratory sides of thev shaft axis and on a straight line passing through the Iatter,'theirindividual eccentriceffects would cancel one another out and the net amplitude of interaction would be zero. The other extreme would be to place the individual centers of mass on the same side of the shaft axis in transverse alignment with one another, whereupon, the amplitude'of vibrationY would be at its maximum due to the additive effect of the Weights.4v Between these two extremes lies a continuous range of` amplitudes that can Y be selectedjto it`l` any situation.-` The necessity for varying the amplitude of vibration'hasalready been explained in detail. The frequency of vibration can, of course, be altered by using a variable speed motor or changing the ratio of the drive and driven pulleys; however, being able to vary the amplitude appears to be much more significant than varying the frequency.

While both weights have been shown adjustable, it is obvious that one may be fixed on the shaft. The set screws on both are provided primarily for ease in assembly and in case the size of the weights needs to be changed for some reason.

Having thus described the several useful and novel features of the rock-polishing machine of the present invention, it will be seen that the many worthwhile objectives for which it was designed have been achieved. Although but a single specific embodiment of the invention has been illustrated and described herein, I realize that certain changes and modifications therein may well occur to those skilled in the art within the broad teaching hereof; hence, it is my intention that the scope of protectio-n afforded hereby shall be limited only insofar as specifically set forth in the appended claims.

What is claimed is:

1. A polishing machine for rocks and the like comprising, an upstanding frame including a base and four uprights arranged at the corners of a rectangle, a motor having a double-ended drive shaft mounted on the base, a first pair of pulleys mounted on opposite ends of the motor drive shaft, tension springs having their upper ends attached to each of the uprights in position to hang downwardly therefrom inside the frame, a platform resiliently suspended from the lower ends of the springs for translatory movement between the uprights in spaced parallel relation above the base, a driven shaft journalled for rotation on the underside of the platform in spaced paralel relation `above the drive shaft, a second pair of pulleys fastened at opposite ends of the driven shaft in verticallyaligned relation to the rst pair thereof, a rock-holding vessel mounted atop the platform for translatory movement therewith, at least one eccentric weight carried by the driven shaft adapted upon rotation of the latter to impart vibratory motion to the platform and associated rock-holding vessel, and belts operatively connecting the vertically-aligned pulleys on the drive and driven shafts, said belts being of a length adapted to pre-load the springs, said belts and springs cooperating to limit the vibratory movement imparted to the platform and vessel to substantially vertical planar motion in a plane normal to the axis of rotation of the driven shaft.

2. The rock-polishing machine as set forth in claim 1 in which the rock-holding vessel has a semi-cylindrical bottom whose axis lies in spaced substantially parallel relation above the driven shaft axis.

3. The rock-polishing machine as set forth in claim 2 in which two eccentric weights are fastened in side-byside relation on the driven shaft, one of said weights being rotatable relative to the other for the purpose of adjusting the resultant center of mass in relation to the driven shaft axis thereby enabling the lamjplitudet of vibration to be varied.

4. The rock-polishing machine as set forth in claim 2 in which a removable resilient liner covers the inside of the rock-holding vessel.

5. The rock-polishing machine as set forth in claim 1 in which two eccentric weights are fastened in side-by-side relation on the driven shaft, one of said Weights being rotatable relative to the other for the purpose of adjusting the resultant center of mass in relation to the driven shaft axis thereby enabling the amplitude of vibration to be varied.

6. The rock-polishing machine as set forth in claim 1 in which a removable resilient liner covers the inside of the rock-holding vessel.

References Cited by the Examiner UNITED STATES PATENTS 1,757,810 5/30 Newman et a1. 209-508 2,555,6884 6/51 Flam 259--72 2,973,606 3/61 Brandt 51-163 LESTER M. SWINGLE, Primary Examiner.

J. SPENCER OVERHOLSER, Examiner. 

1. A POLISHING MACHINE FOR ROCKS AND THE LIKE COMPRISING, AN UPSTANDING FRAME INCLUDING A BASE AND FOUR UPRIGHTS ARRANGED AT THE CORNERS OF A RECTANGLE, A MOTOR HAVING A DOUBLE-ENDED DRIVE SHAFT MOUNTED ON THE BASE A FIRST PAIR OF PULLEYS MOUNTED ON OPPOSITE ENDS OF THE MOTOR DRIVE SHAFT, TENSION SPRINGS HAVING THEIR UPPER ENDS ATTACHED TO EACH OF THE UPRIGHTS IN POSITION TO HANG DOWNWARDLY THEREFROM INSIDE THE FRAME, A PLATFORM RESILIENTLY SUSPENDED FROM THE LOWER ENDS OF THE SPRINGS FOR TRANSLATORY MOVEMENT BETWEEN THE UPRIGHTS IN SPACED PARALLEL RELATION ABOVE THE BASE, A DRIVEN SHAFT JOURNALLED FOR ROTATION ON THE UNDERSIDE OF THE PLATFORM IN SPACED PARALEL RELATION ABOVE THE DRIVE SHAFT, A SECOND PAIR OF PULLEYS FASTENED AT OPPOSITE ENDS OF THE DRIVEN SHAFT IN VERTICALLYALIGNED RELATION TO THE FIRST PAIR THEREOF, A ROCK-HOLDING VESSEL MOUNTED ATOP THE PLATFORM FOR TRANSLATORY MOVEMENT THEREWITH, AT LEAST ONE ECCENTRIC WEIGHT CARRIED BY THE DRIVEN SHAFT ADAPTED UPON ROTATION OF THE LATTER TO IMPART VIBRATORY MOTION TO THE PLATFORM AND ASSOCIATED ROCK-HOLDING VESSEL, AND BELTS OPERATIVELY CONNECTING THE VERTICALLY-ALIGNED PULLEYS ON THE DRIVE AND DRIVEN SHAFTS, SAID BELTS BEING OF A LENGTH ADAPTED TO PRE-LOAD THE SPRINGS, SAID BELTS AND SPRING COOPERATING TO LIMIT THE VIBRATORY MOVEMENT IMPARTED TO THE PLATFORM AND VESSEL TO SUBSTANTIALLY VERTICAL PLANAR MOTION IN A PLANE NORMAL TO THE AXIS OF ROTATION OF THE DRIVEN SHAFT. 